place cursor in find field when opening dialog – the time I've lost when I've not paid attention and FM has interpreted what should have been a find string as a command

find/change text+style

Except for the last one, all these ideas have been implemented meanwhile (in FM 12 and 2015). In FrameMaker (2015 Release) you now have Regular Expressions (aka "RegEx") for Find & Replace. You have a (session based) history list for both the find and replace string (if nothing is selected the last used string is used). If some text is selected and you open the Find/Change dialog, the selected text is automatically copied into the find term. When you open the Find/Change dialog, the cursor is automatically placed in the Find field.